buildgrid/server/bots/instance.py

@@ -66,7 +66,9 @@ class BotsInterface:
         self._bot_sessions[name] = bot_session
         self.logger.info("Created bot session name=[{}] with bot_id=[{}]".format(name, bot_id))
 
-        for lease in self._scheduler.create_leases():
+        # For now, one lease at a time.
+        lease = self._scheduler.create_lease()
+        if lease:
             bot_session.leases.extend([lease])
 
         return bot_session
@@ -83,8 +85,11 @@ class BotsInterface:
         del bot_session.leases[:]
         bot_session.leases.extend(leases)
 
-        for lease in self._scheduler.create_leases():
-            bot_session.leases.extend([lease])
+        # For now, one lease at a time
+        if not bot_session.leases:
+            lease = self._scheduler.create_lease()
+            if lease:
+                bot_session.leases.extend([lease])
 
         self._bot_sessions[name] = bot_session
         return bot_session

buildgrid/server/scheduler.py

@@ -108,10 +108,11 @@ class Scheduler:
         if state in (LeaseState.PENDING.value, LeaseState.ACTIVE.value):
             self.retry_job(name)
 
-    def create_leases(self):
-        while self.queue:
+    def create_lease(self):
+        if self.queue:
             job = self.queue.popleft()
             job.update_execute_stage(ExecuteStage.EXECUTING)
             job.create_lease()
             job.lease.state = LeaseState.PENDING.value
-            yield job.lease
+            return job.lease
+        return None

tests/integration/bots_service.py

@@ -129,7 +129,7 @@ def test_number_of_leases(number_of_jobs, bot_session, context, instance):
     request = bots_pb2.CreateBotSessionRequest(bot_session=bot_session)
     response = instance.CreateBotSession(request, context)
 
-    assert len(response.leases) == number_of_jobs
+    assert len(response.leases) == min(number_of_jobs, 1)
 
 
 def test_update_leases_with_work(bot_session, context, instance):